Wanting to perform LED swap/upgrade,

[StatuSChecKa]

Good day, I have attempted a few searches with no luck.
I wish to swap out a few (or all) the LEDs on my PRO-97 with another color.
Has anyone had any luck or knowledge with this activity. I am into modifications with my vehicle and such, but when it comes to my scanner, I have only disassembled completely so I could installed my new front case.
It appears the LED soldering and unsoldering would be easy, and LED replacement would be very inexpensive.
Does anyone know the specs of the existing LED's? Or any other info? Or any color suggestions. I'm thinking blue, or green. Red would be too hard to see the text.

Thanks.

[gewecke]

What's wrong with the original backlighting that makes you want to change it?
N9ZAS

[dwh367]

Originally Posted by gewecke

What's wrong with the original backlighting that makes you want to change it?
N9ZAS

It would make it a lot easier to identify if it ever got stolen.

[ddoorman]

Seems llike a lot of work for something that might never occur. Why not just make note of the serial number and use that for ID if the need ever arises?

[qlajlu]

Originally Posted by ddoorman

Seems llike a lot of work for something that might never occur. Why not just make note of the serial number and use that for ID if the need ever arises?

Some people cannot leave well enough alone. He already said he was into modifications.

It must be something to do with "boyz and their toyz" syndrome.

[StatuSChecKa]

Well with some guys if there is an LED somewhere, it will get changed.
I'm not quite like that, but if its easy enough I'll do it.
Nothing is wrong with the orange, but after 3 years....kind of old.
I like change every once in a while.

[dwh367]

Originally Posted by StatuSChecKa

Good day, I have attempted a few searches with no luck.
I wish to swap out a few (or all) the LEDs on my PRO-97 with another color.
Has anyone had any luck or knowledge with this activity. I am into modifications with my vehicle and such, but when it comes to my scanner, I have only disassembled completely so I could installed my new front case.
It appears the LED soldering and unsoldering would be easy, and LED replacement would be very inexpensive.
Does anyone know the specs of the existing LED's? Or any other info? Or any color suggestions. I'm thinking blue, or green. Red would be too hard to see the text.

Thanks.

I have a Radio Shack DX-398 Shortwave Radio that I had Radio Labs modify a long time ago. Their modification "package" includes swapping out the stock LEDs with blue ones. It's still easy for me to see the display so blue LEDs for your scanner might work okay for you. It's one of those deals where you never know until you try.

[StatuSChecKa]

Ya I'm sure it comes orange from the factory for a reason, so it will be easy to see.
When it is mounted in my car, my P97 is about 2 and a half feet from my face. You think I will have trouble seeing the black text in-front of a blue light?

[dracer777]

Wirelessly posted (MOT-QA30/00.72 UP.Browser/7.2.7.5.610 (GUI) MMP/2.0)

On my 396xt, i usually have it set to blue, however, it does get annoying sometimes, hard to see. I would not want a permanently blue display. If i were you, i wouldn't make it blue. Maybe red or green if its permanent.

[MarkWestin]

My (all actually) Uniden BCD396T has blue LEDs. In my opinion, these LEDs are the scanner's worst feature. Black (or dark gray) letters on a blue background are not the easiest for me to see. It would be much better if it was blue letters on a black background. Orange, yellow, green, or red would be much better choices. Even white LEDs would be a better choice than blue. It may not be just a simple LED swap. You may also need to replace the resistors associated with the LEDs as different colors may require different voltages or currents than the original ones did.

Mark

[gmclam]

Originally Posted by StatuSChecKa

I wish to swap out a few (or all) the LEDs on my PRO-97 with another color. Has anyone had any luck or knowledge with this activity. I am into modifications with my vehicle and such, but when it comes to my scanner, I have only disassembled completely so I could installed my new front case. It appears the LED soldering and unsoldering would be easy, and LED replacement would be very inexpensive. Does anyone know the specs of the existing LED's? Or any other info? Or any color suggestions. I'm thinking blue, or green. Red would be too hard to see the text.

Let's see ... they are specified as "orange" in color, AlGaInP in type. There are 13 of them - oh that's lucky. The current limiting resistors in series with them are 100 ohm 1/10W 5%.

As someone mentioned, different color LEDs do have different voltage drops. So you'd need to calculate possible different resistor values and replace them as well so you don't over-current the LEDs and/or transistors driving them. Too little current and they won't be as bright as they should be. If the new LEDs have too high of a drop of voltage then they won't work.

Ironically I've thought about doing this on my PRO-92s or PRO-95s, because those displays are DIM. But they only have a couple of LEDs in them in the first place, and there are limits. In that case I am not certain if the back of the LCD is green or if it will inherit the color of the light behind it.

I wouldn't mind having blue as a BG color, but as mentioned, it just does not provide the contrast necessary to read the display. I'd go with white LEDs but these scanners already light up my bedroom as they are.

[dracer777]

Wirelessly posted (MOT-QA30/00.72 UP.Browser/7.2.7.5.610 (GUI) MMP/2.0)

I do agree blue is a bad color for pure functionality, but i do like the way it looks. I love the blue on my 396. But if i do need absolute functionality, i set it to white.

If you want visible, alot of contrast, yet doesnt light up your room, go red.

[N_Jay]

IN general Red, Amber, Yellow and Green are interchangeable, and Blue and white are interchangeable.

Crossing between the two sets is a little trickier.

[dracer777]

Wirelessly posted (MOT-QA30/00.72 UP.Browser/7.2.7.5.610 (GUI) MMP/2.0)

White is much more visible than a deep, LED blue though.

[gmclam]

Originally Posted by N_Jay

IN general Red, Amber, Yellow and Green are interchangeable, and Blue and white are interchangeable.

That statement is overly generalized. It really depends on the SPECIFIC LED being used.

But if you want to be general, RED will have a forward drop of 2.1 volts and GREEN a forward drop of 2.5 volts. While that might be in the same "family", that 0.4 volts is a big deal when powering from 3.3 volts.

[StinkyB]

Try This Current limiting Resistor calculator for leds it might give you an idea on what resistor value to use. Just need the LED values. (supply voltage, current, ect.)

[gmclam]

Originally Posted by StinkyB

Try This Current limiting Resistor calculator for leds it might give you an idea on what resistor value to use. Just need the LED values. (supply voltage, current, ect.)

That's a nice calculator, but you still have to know the values to give it in order to get an answer.

The circuit in the scanner is a transistor driving several LEDs through 100 ohm resistors (one per LED). Therefore the voltage to each LED circuit will be slightly less than 3.3 volts. I looked up the part and the manufacturer specs it at 1.9 volts forward drop. Using the calculator I get about 12ma of current through the LEDs. That would be 156ma total, which is equal to the extra current I see when the backlight is turned on.

I did some looking at Digi-Key and found an LED selector. I limited the search to 0805 case and not right angle. The list then shows voltages from 1.7 to 3.3 volts. Only LEDs with voltages of 1.7 to 2.2 volts will work from the list. The list also shows colors Blue, Blue-Green, Green, Green-Yellow, Orange, Red & Yellow. I did not go through each color to see if it will work. But hopefully you'll see this is not just a "drop in" change.

EDIT: I just went through the various color selections provided, and Blue or Blue-Green from this manufacturer will NOT work in this scanner. While someone out there might have a slightly lower drop, I doubt it will be enough. The other colors did have LEDs which will work, but unless you're very careful in selecting, you certainly will have to change the resistors as well.

[StinkyB]

Originally Posted by gmclam

That's a nice calculator, but you still have to know the values to give it in order to get an answer.

The circuit in the scanner is a transistor driving several LEDs through 100 ohm resistors (one per LED). Therefore the voltage to each LED circuit will be slightly less than 3.3 volts. I looked up the part and the manufacturer specs it at 1.9 volts forward drop. Using the calculator I get about 12ma of current through the LEDs. That would be 156ma total, which is equal to the extra current I see when the backlight is turned on.

I did some looking at Digi-Key and found an LED selector. I limited the search to 0805 case and not right angle. The list then shows voltages from 1.7 to 3.3 volts. Only LEDs with voltages of 1.7 to 2.2 volts will work from the list. The list also shows colors Blue, Blue-Green, Green, Green-Yellow, Orange, Red & Yellow. I did not go through each color to see if it will work. But hopefully you'll see this is not just a "drop in" change.

EDIT: I just went through the various color selections provided, and Blue or Blue-Green from this manufacturer will NOT work in this scanner. While someone out there might have a slightly lower drop, I doubt it will be enough. The other colors did have LEDs which will work, but unless you're very careful in selecting, you certainly will have to change the resistors as well.

The manufacturer should have the specs, all you need is the Supply Voltage, Current Drain,LED Voltage(which the scanner may not have enough of) You will find that red LED's draw the least current, and Blue/White draw more. As you climb the color spectrum(ROYGBIV) the more current, and or voltage you need.

[N_Jay]

I may be wrong, but I think it is the voltage that goes up, but the current stays about the same.

[gmclam]

Originally Posted by StinkyB

The [LED] manufacturer should have the specs,

Which I provided a link to....

all you need is the Supply Voltage,

Which is 3.3 volts minus a nominal drop across the switching transistor of 0.1 volts (net 3.2 volts).

Current Drain,

What you need to understand is how much light output you get for a specific amount of current used and/or what the current limits of the LED are.

LED Voltage(which the scanner may not have enough of)

Same as above -- 3.2 volts net to the LEDs.

You will find that red LED's draw the least current, and Blue/White draw more. As you climb the color spectrum(ROYGBIV) the more current, and or voltage you need.

The LEDs are only going to draw as much current as you let them. What you mean to say is that the voltage drop across the LED increases as you climb the color spectrum. But then you change the chemical makeup of the LED and that puts you on a new path. This is why every red LED out there does not have exactly the same voltage drop. Efficiency is another issue. Cheap LEDs do not output as much light for the same current supplied as better "high efficiency" LEDs.